We still don't know what the Samsung Galaxy S3 is going to look like, but we bet it's going to have the same thin form-factor as its predecessors.

Set to release at a press event in London on May 3, the Samsung Galaxy S3 looks to be the Android smartphone of the moment, packing a speed boost and boasting tight integration with Google's Ice Cream Sandwich OS, along with a few adjective-worthy features and specs. While it's sure to be enough to sell (or ship, rather) a few million units, it remains to be seen how it will stack up against Cupertino's juggernaut.

A source told Andrew Hoyle of CNET UK that the newest member of the ever-expanding Galaxy family will be an incremental update over last year's model, likely in line with the supreme Galaxy Nexus. But, with the iPhone 4S still making major strides and the iPhone 5 waiting in the wings, there are a few key ingredients the Galaxy S3 absolutely must have to keep the heat on Apple.

Display

The Galaxy S2 sported a 4.3-inch WVGA (800 x 480) Super AMOLED with Gorilla Glass display that was slightly improved upon with carrier variants until the Galaxy Nexus blew them all away with a 4.65-inch 1280×720-pixel HD Super AMOLED curved glass display. However, the buzz word on everyone's lips these days is "retina," and the Galaxy S3's screen--no matter how big or bright--won't make much of a splash unless Samsung increases the pixels to match the iPhone.

Design

Boy Genius Report, which originally claimed the Galaxy S3 would come wrapped in a ceramic case, revised its prognostication this week after picking up a few clues from the invitation. Now, the site expects the handset to feature "brushed blue metal, possibly aluminum or stainless steel ... (or) brushed blue plastic," along with a very iPhone-like "physical home button in the middle of the device under the display." Sounds intriguing, we admit, but with all signs pointing to a dramatic redesign with the iPhone 5--possibly even taking advantage of Apple-owned Liquidmetal patents, as Kim In-soon of the Electronic Times reports, to create "an outer surface smooth like liquid," the Galaxy S3 design really needs to be out of this world.

Battery

Samsung may have lapped Apple in the 4G phone race, but as Apple proved with the iPad, it's not just about blazingly fast wireless connections--it's also about battery life. Few of Samsung's 4G offerings can make it more than few hours without a charge, and you can bet Apple won't sacrifice a bit of its impressive battery life for the LTE iPhone. Samsung had better have some tricks up its sleeve, because the 3- to 4-hour Galaxy Nexus just isn't going to cut it.

Graphics

The Galaxy S3 is due to sport a 1.5 GHz quad-core Exynos processor, but all that speed won't do any good if it's not paired with some serious graphics power. Even with less RAM and a slower processor than the Galaxy Nexus, the iPhone 4S still feels snappier (due mostly to the power of iOS); if the same A5X chip that blew the door off the iPad finds its way into the iPhone 5, the Galaxy 3 had better be packing some serious "S" under the hood.

Killer app

The iPhone 4 had FaceTime. The iPhone 4S has Siri. We don't know what the iPhone 5 will have, but we're sure it'll be great. Android phones typically don't carry any handset-specific software features to distinguish themselves from the pack, but it wouldn't be a bad idea for Samsung to start.